1. Field of the Invention
The present invention generally relates to input devices for computers and other devices that need data entry by a person skilled in "Touch Typing" where speed of entry and being environmentally safe are the main concern.
2. Description of the Prior Art
There are no environmentally safe keyboards commercially available or prior art to date that can be used for Touch Typing or where speed of entry is addressed.
One type of keyboard that is environmentally safe and is accepted by the largest number of users is commercially available in the form of a keyboard with membrane switches. Membrane being one that has etched tracks on a printed circuit board (PCB) and over top of the tracks is a conductive membrane that is deflected by a persons finger to the extent it connects the tracks on the PCB giving a switch closure location to the host device. The main drawbacks of these devices are the pressure to make the contact is high and the life expectancy is only one to three million operations because the key domes break due to flexing. These keyboards come in a variety of key patterns, from standard looking typewriter to square matrix types, none of which are being used for Touch Typing.
The second type is made from standard individual switch type keyboards that are used for data entry to computers. In particular they put commercially available covers over the keyboard that only seal from the top, are unsightly to the professional and also restrict Touch Typing.
Disclosures and letters patents have disclosed various other methods of keyboards. None of which are commercially available. They use emitters and detectors for input coordinates for keys. All operate with a fixed grid of recesses for keys and emit the light beam through various types of lenses at each key location, to name two: IBM Technical Disclosure Bulletin, Vol. No. 4, September 1977, S75180086M and U.S. Pat. No. 4,387,367, Fisher. Both, as others, are not for Touch Typing because your finger must go into a hole in a fixed grid key location to block the light path. A person skilled in Touch Typing is only concerned about what they are looking at, the data that is being displayed on the display and not where they are putting their trained fingers. With a standard key switch type of keyboard it does not matter where you touch the key cap only that you touch the right one. The typist may put their finger in the exact same location each time they type a key, but the location could be anywhere on the key cap, and they are not expecting to hit a hole or individual recess. These types of keyboards are also not easily cleaned because of the plurality of key location recesses.
Other Letters Patents have been allowed for touch screen computer entry devices over CRT'S. They display various patterns on the CRT for persons wanting to interface with the device. Some of the patterns have been in a pattern similar to the standard typewriter, but the attitude of the CRT and the intended use is not for Touch Typing. The similar keyboard pattern that can be displayed on the CRT is only there so a person skilled in Touch Typing will know where to look to point their finger to input data. To emphasize this more, most of the key arrangements are a,b,c . . . z and not QWERTY.
One CRT device uses the detector to sense ambient light prior to detecting an object and adjusts the threshold of the sensing circuit. This is disclosed in U.S. Pat. No. 4,243,879, Carroll et al. This disclosure does have short comings, two of which are, it lacks the ability to give a warning of an error or to adjust the output of the emitter if the ambient is of a high enough nature to be out of its preset difference between detection of an object and the ambient threshold. Obviously these disclosures are for detection means to be used over more vertical displays that are recessed to shield ambient light and would not successfully satisfy the more horizontal position of a Touch Typing keyboard. Also in the industrial areas where environmentally safe keyboards are used Underwriters Laboratories states that a CRT must withstand the energy of a five foot pound steel ball drop test and not explode into the operators environment. In practice this means a thick piece of polycarbonate over the CRT. Further emphasizing that CRT'S are not used or intended for Touch Typing.